Molecular chaperones play key roles in protein folding, transport and across membranes, and in response to stressful stimuli. Hsc20 is a DnaJ-type cochaperone protein encoded in a recently discovered operon in E. coli which encodes a DnaK/hsp70type chaperone. No structure for a DnaJ co-chaperone has been determined although a solution MNR structure of the N-terminal 'Jdomain (100 residues) of DnaJ has revealed secondary structure features.We succeeded in overexpressing, purifying and crystallizing Hsc20. Thus, Hsc20 could provide the first complete high resolution crystal structure for proteins of this class. Diffraction data for the native protein have been obtained to 2.6A using conventional x-ray sources. We prepared two heavy atom derivatives by introducing cysteine residues into protein mutagenesis. Crystals of Hg-labeled crystals are too small to provide data for MIR phasing using our x-ray source, and we seek to determine higher resolution data using the synchrotron radiation source.